This Program brings several disciplinary and technical approaches to focus on the process of myocardial contraction. These approaches include 1) ion exchange, particularly Ca ions, on and across myocardial cell membranes in basic states and correlated with changes in function such as inotropies and ischemia, 2) mechanical control or simplification by selective extraction of the multiplicity of factors apparent during contraction so that more specific mechanical and mechanochemical processes can be identified and interrelated, and 3) chemical and mechanical cycling processes. Some of these approaches are most advanced in their application to skeletal muscle but these are directly applicable to myocardial function both in fundamental principle and indeed in their eventual application to heart muscle itself.